william siemens



(No Model.)

C. W. SIEMENS. Electric Lamp.

Patented April 19 ...duc

Nr=l= TERs4 PHOTO-LITHOGRAPHER, WASHlNGToN, D C.

UNITED STATES PATENT OFFICE.

CHARLES W. SIEMENS, OF WESTMINSTER, COUNTY OF MIDDLESEX, ENGLAND.

ELECTRIC LAMP.

SPECIFI'ATION forming part of Letters Patent No. 240,280, dated April 19, 1881.

Application led May 12, 1880.

To all whom it may concern:

Beit known that I, CHARLES WILLIAM SIE- MENS, of Westminster, in the county of Middlesex, England, have invented a new and useful Improvement in Electric Lamps, (for which I have obtained a patent in Great Britain, No. 2,110, bearing date May 27, 187 9,) of which the following is a specification.

According to one part of my present invention I cause the automatic advance or feed of a stick or tube of carbon forming the one pole of an electric lamp toward the other pole, to be determined by the heat produced by the electric arc. This heat, which is very intense at the extreme point of the carbon, in being transmitted longitudinally by conduction decreases proportionately to the distance from the point, so that at a certain distance the temperature is just sufficient to cause surface-combustion of the carbon to commence; and if at that point the advance of the carbon (which may be effected either by gravity or by spring power) be arrested by a stop formed of comparatively incombustible material which just touches the carbon rod or cylinder, the least wear of surface of the carbon round about the stop will permit the rod or cylinder to advance to the limit of the surface-combustion caused by the electric are.

According to one arrangement for carrying out this method of regulating the advance of the carbons, I employ a construction of electric lamps having its carbons arranged horizontaliy,with means of advancing them as they are consumed and replacing them by fresh carbons, and of automatically regulating theirdistance, as I will describe, referring to the accompanying drawings.

Figure l is a Vertical section of the lamp; and Figs. 2, 3, 4, and 5 are views, to an enlarged scale, of parts of one of the carbon-hold ers, hereinafter referred to.

A and B are the two carbons, which lie in guide-troughs M N or tubes open along their upper sides. These guide-troughs are jointed, respectively, to two forked levers, H and I. In the forks of these levers are mounted two barrels, a and I), containing volute springs. A cord (No model.) Patented in England May 27, 1879.

or flexible wire or strip is attached at its one end to each of these barrels, and its other end terminates in a hook, c b,which is inserted in a countersunk hollow at the end of the carbon. The act of drawing out the cords or strings, unwinding them from the barrels for the purpose of inserting their hooks in the ends of thecarbons,winds up the volute springs,which, by their effort to unwind, put tension on the cords or wires, tending to advance the carbons toward each other. Each of the carbons, near its point, is lightly clamped between two stationary chisel-edges, c' c', projecting down from a top piece covering the front part of the guide-trough, and a chisel-edge, c, below the carbon and nearer to its point than the edges c c. The construction of these parts will be understood by reference to Fig. 2, which is a transverse section on line X X of Fig. l; Fig. 3, which is a part longitudinal section on the diagonal line Y Y of Fig. 2; Fig. 4, which is a transverse section on Z Z of Fig. 3, and Fig. 5, which is a plan, looking upward, of the upper edges, c o', against which the carbon bears, and which, as shown, have diagonal serrations.

The edge c is formed on the end of a lever adjustable by a setting-screw, c2, as shown applied to the carbon A in Fig. l; or, instead of a chisel-edge, c, on a lever, the point of a screw, c3, may be employed, as shown applied to the carbon B in Fig. l. By means of the screw c2 or o3 the pressure on the carbon is adjusted so as to clamp it between the edge c or point c3 and the edges c c with sufficient rmness to prevent it from being pushed forward by the force of the spring. As the front end of the carbon becomes, by wasting, thinned round about the point where the edge c or point c3 them. These fresh carbons are made with points coned to enter the countersunk ends of the carbons already in the lamp, and before they are introduced their points are moistened with alittle sirup or caoutchouc solution, which, as the junction approaches the voltaic arc, becomes carbonized by the heat, thus rendering the new carbon continuous with the residue of the old carbon.

Over the carbon points is fixed a reiiector, It, which, while it refiects downward the light of the voltaic are, also protects from its heat the regulating apparatus above.

Under the carbons is a hemispherical bowl, O, of frosted glass or enamel, to diffuse the light and reduce its intensity, as well as to receive such particles as may sparkle oft' the earbons. The bowl O may be inelosed within a wire-netting, o, to support it, and in case of its fracture to prevent the fragments from falling.

The carbon-holders M N, besides being suspended by the levers H and I, rest also on nonconducting rollers fm a, so that they are free to be moved to and fro horizontally.

The automatic regulation of the distance of the carbon points is effected in the following manner:

T is a rod guided to slide vertically up and down. A co1lar,S, screwed on this rod rests on non-conductin g rollers ht' mounted on the arms of the bent levers H and I, the opposite arms of which carry counter-weights. The collar S carries an iron tube, D, which is free to move up or down within a solenoid coil, E, consisting of a number of convolutions of fine wire, offering a high electrical resistance. The rod T has on it a piston, P, fitted to work in a cylinder having one or more small holes through its cover, and on the top of the rod is a cup, Q, which can be charged with shot or other weight, so as to adjust the load on the rod T.

L L are the line-wires conveying electricity to andfrom the lamp. L is connected, through aiiexible metal strip, l, to the one carbon-holder, M, andLl is in like manner connected, through a strip, l', to the other carbon-holder, N. L and L' are also connected together, through the coil of E, by the wires Z2 Z3. Vhen there is no supply of electricity to the lamp the rod T, with the weights upon it bearing down the arms of the levers H and I, separates the earbon points. If, now, the lamp be put in eircuit, the electricity, finding no passage from the one carbon to the other, must pass entirely through the coil E. This causes the iron core D to be attracted upward, relieving the rod T of a large portion of the weight bearing on it. The counter-weights of the levers H and. I thereupon act so as to bring the carbon points together, and the electricity passing through them kindles the lamp 5 but the quantity of electricity passing through the coil E being thus greatly reduced, the attraction of the core D becomes so far diminished that its weight again acts so as to cause separation of the carbons to the distance suitable for the voltaic are. While the lamp continues in action the automatic regulation of the distance of the carbons is maintained in a similar manner. When the carbons are so distant as to offer great resistance to the passage of electricity the coil E becomes more strongly excited, attracting the core D with greater force, and so permitting the approach of the carbons. When the carbons are so near as to offer little resistance to the passage of electricity the coil E is less excited, attracting the core D with less force, and so causing separation of the carbons. The resistance of the air tothe movement of the piston P damps the vertical oscillations of the rod T and the parts connected with it, and the amount of damping may be adjusted by plugging some of the small holes in the cylinder-cover.

Having thus described the nature of my invention and the best means I know of putting it in practice, I wish it to be understood that I am aware a construction of lamp as described in the specification to Shepards English Patent N o. 2,368 of 1858, wherein it was proposed to feed a carbon through a hole in a metal plate, which was intended to act as a stop, allowing the point of carbon to advance through the hole as it was consumed; but the said metal plate would have no such action, as, owin g to its great surface, it would conduct away the heat to such an extent as to prevent any wasting away or yielding of the carbon behind it, and consequently the carbon point originally protruded would merely burn away upto near the plate, whereupon the electric are would become extinguished, no feeding forward of the carbon being possible. I therefore in no way claim such au arrangement for feeding the carbon against a stop surrounding the point; but

l. An electric lamp having horizontal earbons pressed forward by springs against a clamping-pressure near their points, which pressure yields as the carbons waste, allowing them to advance, the carbon-guides being connected to apparatus for automatically regulating their distance, substantially as herein described.

2. In an electric lamp, the conductors of the carbons and their guides, levers adapted to control the movement of the carbons, a solenoid coil of high resistance, its core and connections, as described, whereby said core, as it is more or less attracted by the solenoid, bears with less or greater force on the carboncontrolling lever, substantially as described.

3. The combination of carbon-guide M or N, the volute spring a or b, and its cord or wire, with hook e or b', with the edges c c', and the adjustable edge or point c or c3 in advance of the edges c' c', for the purpose of feeding onward the carbon A or B as it wastes, substantially as herein described.

IOO

ITO

4. The combination of the high-resistance subscribing Witnesses, this 22d da-y of April, 1o

coil E, through which the conductors L L' are 1880.

electrically connected with its core D the levers H and I, and the carbon-guides M, and N C' WILLIAM SIEMENS' 5 for the purpose of automatically regulating the Witnesses distance of the carbons, substantially as herein GHAs. ROCHE, described. GEO. WOOLLETT,

In testimony whereof I have signed my naine Clerks to Messrs. Ridgeway Brothers, 2 Waterto this specification, in the presence of two l loo Place, Pall Mall, London, Notarios. 

